The patent document 1 (listed below) discloses a control system for a vehicle having a continuously variable transmission. According to this system, a target engine rotational speed is calculated for realizing a demand engine output (power) according to an accelerator operation amount at a minimum fuel consumption rate. The gear ratio of the continuously variable transmission is controlled so that an actual engine rotational speed coincides with the target engine rotational speed.
When the gear ratio of the continuously variable transmission is controlled so as to perform the minimum fuel consumption operation as shown in the patent document 1, there is a problem that the acceleration response of the engine which the driver expects is not obtained if the accelerator pedal is rapidly depressed. The patent document 2 (listed below) shows a method for solving this problem.
That is, according to the patent document 2, the transmission control is performed so that the minimum fuel consumption rate operation is performed when the engine operating condition is in a steady state. On the other hand, when the difference between the target engine output according to the accelerator operation amount and the actual engine output is great, a control for shifting from the minimum fuel consumption rate operation to the operation for obtaining good acceleration response, is performed.
Further, the patent document 3 (listed below) discloses a control system in which a target throttle valve opening is calculated from the accelerator operation amount, and an actual throttle valve opening is controlled so as to coincide with the target throttle valve opening. In this control system, a plurality of conversion tables which differ in the conversion characteristics for calculating the target throttle valve opening from the accelerator operation amount are provided, and the suitable conversion table is selected according to the setting of an operation mode switch.